- Joined
- Mar 26, 2001
- Posts
- 3,879
i just purchased another non operational 6 slot that had a standard ram error. After replacing the ram the board booted up but there is one more problem I have never encountered before. There are vertical lines running down the screen. Yeah at first I tried the standard connector cleaning but it didn't work. I observed however when I moved the cart from slot to slot I got the EXACT same graphic problem which brought me to the conclusion that all slot are being affected by a common malfunction.
I have another fully working 6 slot on hand so I took the top board ( cart board ) off the fully working 6 slot and placed it on the six slot that I am having problem with and observed the graphic problem with away so the problem must be with the original top cart pcb that I had removed.
The problem is I do not know where to start to look for problems with this thing as it is jam packed with emitter followers and multiplexers. I of course explored the obvious and tried to find broken traces but I do not see any. I think I might have a faulty component and it has to be common enough to affect all the slots. The 74LS244 emitter followers seem to be associated with seperate slots so I am guessing if one of them fail only the slot associate with the bad component would fail. The 74F251APC multiplexers I discovered any one IC can be associated with all 6 slots.
Does anyone out there primarily have the pinout for the MVS cartridge slot so I can isolate what pin controls the graphic to narrow things down, it does not mater if its a 1 slot, 2slot or what ever. Also I would appreciate any experience you would have to offer to repair this problem.
I have another fully working 6 slot on hand so I took the top board ( cart board ) off the fully working 6 slot and placed it on the six slot that I am having problem with and observed the graphic problem with away so the problem must be with the original top cart pcb that I had removed.
The problem is I do not know where to start to look for problems with this thing as it is jam packed with emitter followers and multiplexers. I of course explored the obvious and tried to find broken traces but I do not see any. I think I might have a faulty component and it has to be common enough to affect all the slots. The 74LS244 emitter followers seem to be associated with seperate slots so I am guessing if one of them fail only the slot associate with the bad component would fail. The 74F251APC multiplexers I discovered any one IC can be associated with all 6 slots.
Does anyone out there primarily have the pinout for the MVS cartridge slot so I can isolate what pin controls the graphic to narrow things down, it does not mater if its a 1 slot, 2slot or what ever. Also I would appreciate any experience you would have to offer to repair this problem.
